为什么我尝试使用C＃写入日志文件时获得“不支持URI格式”异常？

Question

I am writing a method that take a string containing a message and write this string into a log file.

I have done in this way:

internal static void WriteLogFile(string messageLog)
{
    if (messageLog == "")
    {
        messageLog = "L'import delle regole di inoltro è andato a buon fine. Tutte le regole di inoltro sono state inserite";
    }

    try
    {
        var filePath = new Uri(Assembly.GetEntryAssembly().GetName().CodeBase);

        Thread.CurrentThread.CurrentCulture = new CultureInfo("it-IT");
        CultureInfo ci = new CultureInfo("it-IT");

        File.WriteAllText(filePath + "log.txt", messageLog);

        Thread.CurrentThread.CurrentCulture = new CultureInfo("it-IT");

    }
    catch (Exception ex)
    {
        throw ex;
    }
}

The problem is that when perform this line:

File.WriteAllText(filePath + "log.txt", messageLog);

I am obtaining the following exception:

"URI formats are not supported."

What is wrong? What am I missing? How can I try to fix it?

Answer 1

Try this class:

using System;
using System.IO;

namespace YourNameSpace.Models
{
    public class Logger
    {
        private Object Locker { get; set; }
        public string Path { get; set; }

        public Logger(string path)
        {
            Locker = new Object();
            Path = path;
        }

        public void Log(string message, params object[] args)
        {
            lock (Locker)
            {
                string messageToLog = string.Format("{0} - {1}", DateTime.Now, string.Format(message, args));
                string path = System.IO.Path.Combine(Path, string.Format("{0}.txt", DateTime.Today.ToString("yyyyMMdd")));
                Directory.CreateDirectory(Path);
                File.AppendAllLines(path, new string[] { messageToLog });
            }
        }
    }
}

Answer 2

I'm assuming your problem is to write a log file in the same folder as your executable. Try to use the Location property:

var filePath = Assembly.GetEntryAssembly().Location;

That will return a valid path that you can concatenate with the file name, or use Path.Combine method.

Answer 3

Because WriteAllText does not support a URI format, and you're using a URI.

Per https://docs.microsoft.com/en-us/dotnet/api/system.io.file.writealltext?view=netframework-4.8 , you need to pass it a string path.

As others have suggested, you should use GetPath if you want to create the file locally, or some other method depending where you want the file to go.